The invention is directed to an apparatus for the loading of evaporators (vaporizers) in vapor coating plants with shaped pieces of vapor coating materials.
Thin layers of materials, especially metals can be obtained in a relatively simple manner by vaporizing the corresponding materials in a vacuum and depositing the vapors formed on the corresponding substrates. Thereby the vaporization of the materials to be applied takes place in so-called evaporators by heating or also by means of electron beams.
The vapor coating of thin layers on limited surfaces with a homogeneous vapor coating materials is relatively simple. Complicated apparatuses are necessary in the vapor deposition of continuous belts, in the vapor coating of alloy layers or several layers of different materials, above all on account of the continuous loading of the evaporator with the vapor coating materials without breaking the vacuum, which would lead to deterioration of the quality of the layer. In breaking the vacuum for the purpose of new loading of the evaporator there is the difficulty that a multiple pumping out of the vapor coating plant is uneconomical.
It is known to apply coatings made of several components on substrates by vapor coating in a vacuum by bringing the substrate successively over evaporators having the corresponding materials (German OS 1910332). However, this process and apparatus can only operate with a limited amount of vapor coating materials. The same disadvantages occur if evaporators with different vapor coating materials are arranged on a rotatable plate (indexable table) and are heated successively (German AS 1298833).
Furthermore, there are known apparatus with which the vapor coating materials can be supplied continuously to the evaporators during the vapor coating process or while maintaining the vacuum. Thus for example, in German patent 752141 the vapor coating material in wire form is drawn off from a supply roll and supplied directly to heated crucible evaporator, where it is vaporized and is deposited on the substrate. Besides it is known from German AS 1032998 to allow the materials to be vaporized to fall in the form of small particles through a suitable apparatus on the highly heated evaporator. However, these loading apparatuses have the disadvantage that they must be cooled separately because of the high heat load in the plant and in the vapor coating can cast disturbing "shadows".
Therefore it was the problem of the present invention to provide an apparatus for loading evaporators in vapor coating plants having shaped pieces made of vapor coating materials with which the evaporator can be repeatedly loaded without breaking the vacuum, without there being required a special cooling and without there occurring a "casting of shadows".